40 MISC. PUBLICATION 4 98, U. S. DEPT. OF AGRICULTURE 



regions of the Tropics. All parts of the plant may be affected 

 except possibly the roots, but as already stated the chief damage is 

 done to ripe or nearly ripe fruits. Among the factors favoring in- 

 fection the most important are high temperature, high humidity, the 

 presence of bruises or wounds, and the degree of maturity of the fruit. 

 There are differences in varietal susceptibility, but these are of little 

 significance on the markets of the United States since banana imports 

 into this country consist almost exclusively of one variety, the Gros 

 Michel. 



CONTROL MEASURES 



Careful handling of the fruit throughout the marketing process 

 is of the utmost importance in controlling anthracnose. It is also 

 important to clean out ripening rooms frequently and to treat the 

 walls and floor with some disinfectant. The practice of putting hay 

 or sawdust on the floor is an unsafe one, for if such material is 

 allowed to remain indefinitely it becomes contaminated with banana 

 refuse and is then a source from which spores may spread to healthy 

 fruit placed in the room. 



(See 4, 120, 123, 128, 129.) 



CHILLING INJURY 



If green bananas are exposed to temperatures below about 56° F. 

 they are in danger of damage from chilling injury. The actual oc- 

 currence of injury and its severity depend on how long the fruit is 

 exposed to the chilling, on how low the temperature goes, and to a 

 large extent on the character of the fruit. The less mature fruit is 

 very sensitive to cold and is injured by exposure to temperatures close 

 to 56° for only 4 or 5 days; more mature fruit is more resistant and 

 will stand a temperature of 53° to 5C° for 10 or 11 days without 

 injury. 



The first visible symptom of chilling injury is the development of 

 a dull yellow color instead of a healthy bright one. Frequently there 

 is a fine brown streaking in the skin, which is the result of changes 

 in the mucilage ducts. In severely chilled fruit the skin becomes 

 brown all over and eventually turns black. Chilled fruit is easily 

 discolored by the slightest bruise. 



Slight chilling seems to produce only surface injury because it has 

 been found that in bananas showing the milder symptoms just de- 

 scribed, the ripening of the pulp proceeds at a normal rate after the 

 fruit has been brought to a temperature favorable for ripening. 

 Severely chilled fruit does not ripen properly and consequently has 

 poor flavor. No treatment subsequent to chilling can improve color. 

 Slightly chilled fruit can be marketed, but it should be ripened and 

 used as quickly as possible. 



If green healthy bananas are broken or cut, a milky, glutinous 

 juice (latex) exudes freely, chiefly from the skin and to a slight 

 extent from the pulp. In chilled fruit this exudation of latex does 

 not occur. Its absence, however, is not a sure indication of chilling 

 injury, because latex exudes very little if at all from the peel of 

 turning or ripe fruit. 



(See 127, 128, 129, 130.) 



